Instead of proprietary point-to-point connections between sensors and central evaluation units, “bus approaches” are being increasingly used in vehicles. The UN (Local Interconnect Network) bus is typically used in vehicles for this purpose as a standardized and cost-optimized bus system.
With the standard LIN protocol, a user sends its data in a dedicated frame in each case. As a result of the control data which are required for a frame, the net data transmission rate drastically worsens when a single user transmits only a small amount of data. According to the related art (LIN specification), the LIN protocol provides for each user to transmit its data with the aid of one or multiple dedicated frames, identified by a frame ID.
German Published Patent Appln. No. 10 2009 027 201 describes a method according to which multiple users share a frame, with the goal of reducing the total required control data. The position to which each user writes its data within the shared frame is established by its clear identifier. The positions of the data are thus statically established. All sensors must send for a valid frame to be created. The protocol is optimized for the case in which all users have new data to be sent in each cycle. The net data rate is then the highest. However, the net data rate decreases when individual users have no new data to be sent in one cycle. They must then send “empty bytes,” whereby bandwidth is unnecessarily occupied or the cycle time is unnecessarily long. The approach described in the above-mentioned publication is also referred to as “VLINC” and will also be described by this designation hereafter in the description.